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Topic Review (Newest First)
08-19-2010 09:29 PM
jeraldfler Re borla

My bro has a pypes exhaust system
07-14-2010 01:28 AM
rrich The 10 hour or more deep cleaning of the memory is certainly worth a try - it costs nothing and is easy.

How much do you want to spend throwing parts at it?
Whenever you change sensors or major things like the exhaust, the computer has to relearn all about them. Since it's accustomed to the old part, often it gets confused and takes awhile to adjust to the new. Doing the 10 hour reset to default really helps sometimes.
Of course there's no guarantee.

That code, po431, indicates it "thinks" the converter is not up to the expected temperature - based on the old restrictive exhaust. But now you have better flow, different temps. The converter will run a little cooler now.
The downstream sensor (trim) detects a change, the ECM tells you. Resetting to default the entire system gets the opportunity to start over.

Sometimes your home PC does weird things - but restarting/rebooting it gets it working again - same idea.
07-14-2010 12:23 AM
AzTJ Check out partstrain.com for new sensors... I just ordered both for my '97 for less than what Napa wanted for one.
07-14-2010 12:16 AM
IndyJeepMan I have the borla cat-back and have no troubles but definantly sounds like an o2 sensor.
07-13-2010 11:39 PM
s3nt3nc3d OBD-II Trouble Code: P0431 Warm Up Catalyst Efficiency Below Threshold (Bank 2)

Sounds like an O2 sensor is on the way out and it's causing it to run pig rich...I think the upstream O2 sensor(s) are the ones that are used to determine the fuel/air mixture but don't quote me on that.
07-13-2010 10:30 PM
rubi06 also just filled up and noticed im only getting 7.5mpg, and feeling a bit of low end lag not sure if this is related to the p0431 code.
07-13-2010 08:16 PM
rubi06
Quote:
Originally Posted by rubi06 View Post
well you are right, i tried and after 10 miles the light is back on. will the ten hour disconnect do the trick? is this a common problem when you install an exhaust, my old jeep was a 90 yj and i never had to worry about any of this stuff! thanks for your help!
just checked the code is po431
07-13-2010 07:30 PM
rubi06
Quote:
Originally Posted by rrich View Post
Unfortunately that method doesn't do the job most of the time. It's been proven many many times.

I'm surprised that Quadratec is promoting that bull. Normally they are straight on.
well you are right, i tried and after 10 miles the light is back on. will the ten hour disconnect do the trick? is this a common problem when you install an exhaust, my old jeep was a 90 yj and i never had to worry about any of this stuff! thanks for your help!
07-12-2010 11:52 PM
rrich Unfortunately that method doesn't do the job most of the time. It's been proven many many times.

I'm surprised that Quadratec is promoting that bull. Normally they are straight on.
07-12-2010 09:39 PM
rubi06 Thanks everyone for all of your suggestions, my friend did clear the code and it did come back within a few days, i have checked the wiring and all looks good, dont worry i had no plans on replacing the cats! i figured it had something to do with the new high flow exhaust. i can not remember the code number, hoevere i do plan on resetting the ECU. I found this information on quadratec.com , thanks again i will let you know if this works.

Jeep Electronic Control Unit Reset

--------------------------------------------------------------------------
When installing new power or performance accessories how does the computer for the Jeep know that it has a new accessory? Most of the time the computer does not. The computer would need to be reset to take full potential of the performance accessories you have added.

The Electronic Control Module, or ECU as its commonly called, stores the information for your vehicle and your driving habits in its memory. The memory is maintaned by a series of capacitors that hold a charge and maintain power for the ECU when the vehicle is turned off. The following procedure will allow you to reset the memory and allow the computer to 're-learn' how to drive by adjusting to the drivers habits and the vehicles modifications.



1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.

2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.

3. Reconnect the positive cable to the battery.

4. Turn the key to on but do not start.

5. Turn the headlights on.

6. Turn the headlights off.

7. Turn the key off.


The ECU has now been reset to its factory settings. For the next 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.
07-12-2010 08:59 AM
rrich What is or what was the number of the code?
07-12-2010 08:55 AM
Brad[LK1] If you were doing any pounding on the old exhaust or struck the pipe near the O2 sensor to either remove the old one or put on the new one, its likely the internals of the O2 sensor are damaged and it just needs replace....Catalytic converters just dont usually up and crap like that....You'd hear a leak that bad if it was the case and it'd would be coming from the header or down pipe
07-12-2010 04:40 AM
rrich Disconnecting for an hour will clear the code, but it won't reset the ECM memory. With the new less restrictive exhaust the ECM needs to be reset to default - disconnect the battery for at least 10 hours.
07-12-2010 12:41 AM
IndyJeepMan Just whatever you do, dont fall in a mechanics trap and install a new cat. Please. lol

Make sure all welds are good no holes.
07-12-2010 12:15 AM
doclouie I would also check the wiring that connects to the sensor after the CAT. If your Jeep's exhaust is like mine there is a sensor right after the CAT and the wiring could easily be damaged.
07-11-2010 11:16 PM
cavediverjc Disconnect your battery for an hour, then reconnect the cables. See if your CEL comes back on. That's the first step.
07-11-2010 10:33 PM
rubi06
Borla cat back installed now CEL is lit

Hello, i have a 2006 Rubicon and i recently installed a borla cat back system on it. no other mods are installed after the install my CEL is on mechanic says code is cat not heating up to temp/efficency. prob causes could be an exhaust leak, a bad cat , a bad 02 sensor. i was wondering if anyone else has had this problem anh what is the best way to fix?

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